Minimally invasive surgical techniques typically include accessing the tissue through a small opening or port into the body. Minimally invasive procedures may include laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device, and may be carried out through the skin or through a body cavity or anatomical opening. This may result in shorter hospital stays, or allow outpatient treatment.
Unfortunately, the use of minimally-invasive techniques has often required a loss in control of the treatment device or implant, as the treatment sites are often deep within the body, proving both difficult to access, as well as difficult to manipulate the device when the body region is minimally invasively accessed. In particular, finding leverage to position or manipulate minimally invasive devices once deployed has proven extremely difficult. For example, most procedures are performed from a single (minimally invasive) opening through the body to access the treatment site. Thus, any devices or implants delivered through this opening must be controlled externally through the single opening. As a result, complex and expensive tools have been created to allow manipulation of distally-positioned devices or implants within the body.
Even in variations of minimally invasive procedures in which a second access port is used, coordination of the two access ports at the target has proven difficult, particularly when one or more devices are inserted through different access ports and required to meet at an internal site. Such minimally invasive techniques often require the additional use of visualization devices to guide and/or confirm device position and operation.
Finally, manipulation of implants and devices using any of these minimally invasive techniques has also proven difficult. For example, when treating small or enclosed body regions such as joints, or regions surrounded by sensitive non-target tissue, manipulation of a device or implant within this space has been limited by the ability to control the distal end of the device from a proximal position. When a single access point is used, the device or implant must generally be ‘pushed’ into position within or along an access device. An elongate member (e.g., a cannula or guide) may be used, and the control of an implant or other device depends on the configuration of the access elongate member. Thus, the application of force by the implant or treatment device may depend on the application of force from the proximal end, at some distance from the distal end where the implant or treatment device is located. This may lead to undesirable and dangerous kinking, bending, and torqueing of the access device and/or implant.
Described herein are methods, devices and systems for treating tissue by first placing a guidewire (or “pullwire”) in position within the body, and then using the guidewire to position, anchor and/or treat the tissue. In general, these methods and systems are “bimanual” procedures, in which the implant or tissue modification device is controlled within the body from two separate locations outside of the body. The devices, methods and systems described herein may allow precise control and anchoring of one or more devices, and therefore precise treatment of tissue, and may address many of the issues raised above. Although the methods described herein may be particularly suitable for minimally invasive (e.g., percutaneous) treatment of tissue, they may also be used for open or semi-open treatments.
In one subsection of this document, described herein are devices, methods and systems that relate generally to medical/surgical devices and methods. More specifically, they may relate to guidewire systems and methods for advancing one or more surgical devices between tissues in a patient.
In recent years, less invasive (or “minimally invasive”) surgical techniques have become increasingly more popular, as physicians, patients and medical device innovators have sought to achieve similar or improved outcomes, relative to conventional surgery, while reducing the trauma, recovery time and side effects typically associated with conventional surgery. Developing less invasive surgical methods and devices, however, can pose many challenges. For example, some challenges of less invasive techniques include working in a smaller operating field, working with smaller devices, and trying to operate with reduced or even no direct visualization of the structure (or structures) being treated. These challenges are compounded by the fact that target tissues to be modified often reside very close to one or more vital, non-target tissues, which the surgeon hopes not to damage. One of the initial obstacles in any given minimally invasive procedure, therefore, is positioning a minimally invasive surgical device in a desired location within the patient to perform the procedure on one or more target tissues, while avoiding damage to nearby non-target tissues.
Examples of less invasive surgical procedures include laparoscopic procedures, arthroscopic procedures, and minimally invasive approaches to spinal surgery, such as a number of less invasive intervertebral disc removal, repair and replacement techniques.
One area of spinal surgery in which a number of less invasive techniques have been developed is the treatment of spinal stenosis. Spinal stenosis occurs when neural and/or neurovascular tissue in the spine becomes impinged by one or more structures pressing against them, causing one or more symptoms. This impingement of tissue may occur in one or more of several different areas in the spine, such as in the central spinal canal, or more commonly in the lateral recesses of the spinal canal and/or one or more intervertebral foramina.
FIGS. 352-354 show various partial views of the lower (lumbar) region of the spine. FIG. 352 shows an approximate top view of a vertebra with the cauda equina (the bundle of nerves that extends from the base of the spinal cord through the central spinal canal) shown in cross section and two nerve roots exiting the central spinal canal and extending through intervertebral foramina on either side of the vertebra. The spinal cord and cauda equina run vertically along the spine through the central spinal canal, while nerve roots branch off of the spinal cord and cauda equina between adjacent vertebrae and extend through the intervertebral foramina. Intervertebral foramina may also be seen in FIGS. 353 and 354, and nerves extending through the foramina may be seen in FIG. 353.
One common cause of spinal stenosis is buckling and thickening of the ligamentum flavum (one of the ligaments attached to and connecting the vertebrae), as shown in FIG. 352. (Normal ligamentum flavum is shown in cross section in FIG. 354) Buckling or thickening of the ligamentum flavum may impinge on one or more neurovascular structures, dorsal root ganglia, nerve roots and/or the spinal cord itself. Another common cause of neural and neurovascular impingement in the spine is hypertrophy of one or more facet joints (or “zygopophaseal joints”), which provide articulation between adjacent vertebrae. (Two vertebral facet superior articular processes are shown in FIG. 352. Each superior articular process articulates with an inferior articular process of an adjacent vertebra to form a zygopophaseal joint. Such a joint is labeled in FIG. 354.) Other causes of spinal stenosis include formation of osteophytes (or “bone spurs”) on vertebrae, spondylolisthesis (sliding of one vertebra relative to an adjacent vertebra), facet joint synovial cysts, and collapse, bulging or herniation of an intervertebral disc into the central spinal canal. Disc, bone, ligament or other tissue may impinge on the spinal cord, the cauda equina, branching spinal nerve roots and/or blood vessels in the spine to cause loss of function, ischemia and even permanent damage of neural or neurovascular tissue. In a patient, this may manifest as pain, impaired sensation and/or loss of strength or mobility.
In the United States, spinal stenosis occurs with an incidence of between 4% and 6% of adults aged 50 and older and is the most frequent reason cited for back surgery in patients aged 60 and older. Conservative approaches to the treatment of symptoms of spinal stenosis include systemic medications and physical therapy. Epidural steroid injections may also be utilized, but they do not provide long lasting benefits. When these approaches are inadequate, current treatment for spinal stenosis is generally limited to invasive surgical procedures to remove ligament, cartilage, bone spurs, synovial cysts, cartilage, and bone to provide increased room for neural and neurovascular tissue. The standard surgical procedure for spinal stenosis treatment includes laminectomy (complete removal of the lamina (see FIGS. 352 and 353) of one or more vertebrae) or laminotomy (partial removal of the lamina), followed by removal (or “resection”) of the ligamentum flavum. In addition, the surgery often includes partial or occasionally complete facetectomy (removal of all or part of one or more facet joints). In cases where a bulging intervertebral disc contributes to neural impingement, disc material may be removed surgically in a discectomy procedure.
Removal of vertebral bone, as occurs in laminectomy and facetectomy, often leaves the affected area of the spine very unstable, leading to a need for an additional highly invasive fusion procedure that puts extra demands on the patient's vertebrae and limits the patient's ability to move. In a spinal fusion procedure, the vertebrae are attached together with some kind of support mechanism to prevent them from moving relative to one another and to allow adjacent vertebral bones to fuse together. Unfortunately, a surgical spine fusion results in a loss of ability to move the fused section of the back, diminishing the patient's range of motion and causing stress on the discs and facet joints of adjacent vertebral segments. Such stress on adjacent vertebrae often leads to further dysfunction of the spine, back pain, lower leg weakness or pain, and/or other symptoms. Furthermore, using current surgical techniques, gaining sufficient access to the spine to perform a laminectomy, facetectomy and spinal fusion requires dissecting through a wide incision on the back and typically causes extensive muscle damage, leading to significant post-operative pain and lengthy rehabilitation. Discectomy procedures require entering through an incision in the patient's abdomen and navigating through the abdominal anatomy to arrive at the spine. Thus, while laminectomy, facetectomy, discectomy, and spinal fusion frequently improve symptoms of neural and neurovascular impingement in the short term, these procedures are highly invasive, diminish spinal function, drastically disrupt normal anatomy, and increase long-term morbidity above levels seen in untreated patients. Although a number of less invasive techniques and devices for spinal stenosis surgery have been developed, these techniques still typically require removal of significant amounts of vertebral bone and, thus, typically require spinal fusion.
Therefore, it would be desirable to have less invasive surgical methods and systems for treating spinal stenosis. For example, it would be desirable to have devices or systems for positioning a less invasive device in a patient for performing a less invasive procedure. Ideally, such systems and devices would be less invasive than currently available techniques and thus prevent damage to non-target vertebral bone and neural and neurovascular structures. Also ideally, such systems and devices would also be usable (or adaptable for use) in positioning a surgical device in parts of the body other than the spine, such as in joints for performing various arthroscopic surgical procedures, between a cancerous tumor and adjacent tissues for performing a tumor resection, and the like.
In particular, it would be useful to provided devices, systems and methods for gaining access using a guidewire that could be easily exchanged to position and apply tension to a plurality of devices, including surgical devices such as tissue localization devices, tissue modification devices, or the like. Described herein are devices, methods and system which may address these needs.